Founders of the progressive PAC Justice Democrats, which helped elect social-democrats like Alexandria Ocasio-Cortez (D-N.Y.), have launched a new progressive PAC, No Excuses, to raise money for candidates to challenge two incumbent Democrats who favor keeping the Senate filibuster and have expressed willingness to work with Republicans. PAC co-founders Saikat Chakrabarti, Corbin Trent, and Zack Exley…